Abstract integration helpers

[tangrufus]

• I've read the guidelines for Contributing to Roots Projects
• This request isn't a duplicate of an existing request
• This is not a personal support request that should be posted on the Roots Discourse community

Summary

Abstract integration helpers. Something like:

- bin := os.Getenv("TEST_BINARY") 
-  if bin == "" { 
-  	t.Error("TEST_BINARY not supplied") 
-  } 
-  if _, err := os.Stat(bin); os.IsNotExist(err) { 
-  	t.Error(bin + "not exist") 
-  } 
  
-   dummy := os.Getenv("TEST_DUMMY")
- 	if dummy == "" {
- 		t.Error("TEST_DUMMY not supplied")
- 	}

+ bin, dummy = integrationTestHelper.prepareEnvironment()

  // after the tests

+ integrationTestHelper.cleanup(dummy)

integrationTestHelper.prepareEnvironment:

1. Check environment variables are supplied
2. Clone the dummy files into a temporary location (to be deleted by integrationTestHelper.cleanup)
3. return the paths, i.e: bin, dummy

Motivation

Cleaning up becomes problematic when not running tests with docker.

Cloning the dummy files into temporary locations ensure integration tests don't interfere with each others, so that developers don't need to clean up dummy

Cons:

• Tests take longer to run. But I think this is a reasonable trade-off
• premature abstraction is evil

Additional context

trellis-cli/cmd/dot_env_test.go

Lines 151 to 162 in 1741735

	bin := os.Getenv("TEST_BINARY")
	if bin == "" {
	t.Error("TEST_BINARY not supplied")
	}
	if _, err := os.Stat(bin); os.IsNotExist(err) {
	t.Error(bin + "not exist")
	}
	dummy := os.Getenv("TEST_DUMMY")
	if dummy == "" {
	t.Error("TEST_DUMMY not supplied")
	}

[swalkinshaw]

Tests take longer to run. But I think this is a reasonable trade-off

If these are skipped in short mode then it doesn't matter as much?

integrationTestHelper makes sense I think once we have integration tests 👍 I'll probably have more coming with the virtualenv work